Shelled hemp seeds are becoming a popular dietary supplement because of their high protein content and healthful fatty acids. Hemp seeds come from the same plants, Cannabis sativa or C. indica, that produce marijuana, although the plants are cultivated and processed differently so that hemp seeds contain very low levels of psychoactive cannabinols such as delta-9-tetrahydrocannabinol, or THC. Shelled hemp seeds are generally safe, but some people may experience some undesired side effects.
For profitable hemp farming, particularly deep, humus-rich, nutrient-rich soil with controlled water flow is preferable. Waterlogged acidic, compressed or extremely light (sandy) soils primarily affect the early development of plants. Steep and high altitudes of more than 400 m above sea level are best avoided. Hemp is relatively insensitive to cold temperatures and can withstand frost down to −5 °C. Seeds can germinate down to 1–3 °C. Hemp needs a lot of heat, so earlier varieties come to maturation. The water requirement is 300–500 l/kg dry matter. This is around 1/14th that of cotton, which takes between 7,000 and 29,000 l/kg, according to WWF. Roots can grow up to 3 feet into the soil and use water from deeper soil layers.